Stack growler



FIG. 1 is a front view of a stack growler according to my new design;

FIG. 2 is a right side view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is an enlarged top plan view thereof;

FIG. 6 is an enlarged bottom plan view thereof; and,

FIG. 7 is an enlarged perspective view thereof. 

CLAIM The ornamental design for a stack growler, as shown and described. 